74 lines
2.2 KiB
Go
74 lines
2.2 KiB
Go
// Copyright 2020 PingCAP, Inc.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package mathutil
|
|
|
|
import (
|
|
"testing"
|
|
"time"
|
|
|
|
"github.com/stretchr/testify/require"
|
|
)
|
|
|
|
func TestRandWithTime(t *testing.T) {
|
|
rng1 := NewWithTime()
|
|
// NOTE: On windows platform, this Sleep is necessary. Because time.Now() is
|
|
// imprecise, calling UnixNano() twice returns the same value. We have to make
|
|
// sure the elapsed time is longer than 1ms to get different values.
|
|
time.Sleep(time.Millisecond)
|
|
rng2 := NewWithTime()
|
|
got1 := rng1.Gen()
|
|
got2 := rng2.Gen()
|
|
require.True(t, got1 < 1.0)
|
|
require.True(t, got1 >= 0.0)
|
|
require.True(t, got1 != rng1.Gen())
|
|
require.True(t, got2 < 1.0)
|
|
require.True(t, got2 >= 0.0)
|
|
require.True(t, got2 != rng2.Gen())
|
|
require.True(t, got1 != got2)
|
|
}
|
|
|
|
func TestRandWithSeed(t *testing.T) {
|
|
tests := [4]struct {
|
|
seed int64
|
|
once float64
|
|
twice float64
|
|
}{{0, 0.15522042769493574, 0.620881741513388},
|
|
{1, 0.40540353712197724, 0.8716141803857071},
|
|
{-1, 0.9050373219931845, 0.37014932126752037},
|
|
{9223372036854775807, 0.9050373219931845, 0.37014932126752037}}
|
|
for _, test := range tests {
|
|
rng := NewWithSeed(test.seed)
|
|
got1 := rng.Gen()
|
|
require.Equal(t, got1, test.once)
|
|
got2 := rng.Gen()
|
|
require.Equal(t, got2, test.twice)
|
|
}
|
|
}
|
|
|
|
func TestRandWithSeed1AndSeed2(t *testing.T) {
|
|
seed1 := uint32(10000000)
|
|
seed2 := uint32(1000000)
|
|
|
|
rng := NewWithTime()
|
|
rng.SetSeed1(seed1)
|
|
rng.SetSeed2(seed2)
|
|
|
|
require.Equal(t, rng.Gen(), 0.028870999839968048)
|
|
require.Equal(t, rng.Gen(), 0.11641535266900002)
|
|
require.Equal(t, rng.Gen(), 0.49546379455874096)
|
|
require.Equal(t, rng.GetSeed1(), uint32(532000198))
|
|
require.Equal(t, rng.GetSeed2(), uint32(689000330))
|
|
}
|